A number of rare vascular plants are included in the notification of the SSSI; prior to 2008 the vascular plant interest had not been formally assessed using Common Standards Monitoring guidance. Natural England therefore commissioned an assessment of the species of interest based on review of known recent baseline data, desk-based research and targeted fieldwork. The results of work are intended to underpin the Condition Assessment by supplementing information gleaned from past surveys and recording.
Salisbury Plain SSSI has a rare vascular plant assemblage, comprising 13 species according to the citation, potentially scoring 1150 points (see English Nature Research Report 690), which greatly exceeds the generic conservation objective threshold of 200 points. Of the 13 species considered in this report, 11 were found to be present, scoring a total of 900 points. Two species were not found (Dianthus deltoides and Gentianella anglica).